Yisheng Biopharma Co., Ltd, a biopharmaceutical company focusing on research, development, manufacturing, sales and marketing of vaccine products, has announced positive topline results from Phase I clinical trial of PIKA rabies vaccine, an investigational vaccine designed to provide accelerated immune response against post-exposure rabies virus infection.

PIKA rabies vaccine is an innovative rabies vaccine independently developed by Yisheng Biopharma, using a novel double-strand RNA analogue (PIKA), which acts as a toll-like receptor-3 (TLR-3) agonist to the activation of the innate immune cells. This project was named a “National Key Medicine Innovation” in 2013 and funded by the National Ministry of Science and Technology of China.

Rabies infection has a mortality rate of almost 100% after the onset of the clinical symptoms and it remains one of the most fatal acute infectious diseases known, with 60,000 deaths worldwide in 2013, and represents a severe public health problem in China, India and many other developing countries. In addition, as report by Guangxi CDC of China, vaccination failure among post-exposure patients remains a serious challenge, of which 78.1% of subjects died between day 6 and 27 post vaccination. Therefore, fast production of neutralizing antibody (or seroconversion) post vaccination is critical for life saving against the post-exposure rabies infection.

The Phase I clinical study was conducted at the SingHealth Investigational Medicine Unit (IMU) in Singapore, and the trial enrolled 37 healthy volunteers to evaluate the preliminary safety and efficacy of the investigational PIKA rabies vaccine. Highlights of the topline results include

PIKA rabies vaccine was well tolerated and safe, similar to the control vaccine, which is commercially available

PIKA rabies vaccine elicited a multi-specific rabies T cell response

PIKA vaccine with accelerated regimen (3 dosings in 7 days) was able to produce 100% seroconversion on day 14, reaching the standard requirement of rabies vaccine, of which 75.0% of subjects achieved seroconversion on day 7, compared with only 16.7% of subjects reaching seroconversion on day 7 under the standard regimen (4 dosings in 14 days) receiving control vaccine on day 7, which reached statistical significance (p<0.05).

Dr Victor Li, who is overseeing the clinical investigation in Singapore, commented: “We are extremely pleased with the results of this study, which confirms the preclinical study results, PIKA rabies vaccine exhibited good safety profile with no significant difference in terms of side-effects in comparison with the control vaccine, which is commercially available. We are very encouraged by the observation that 75% of subjects under PIKA rabies vaccine were able to reach seroconversion, a critical life saving benefit against post exposure rabies infection. We also believe that the accelerated regimen using 3 dosings within 7 days could greatly improve the vaccination compliance.”

“We are excited to see that this trial confirms and advances the results observed in preclinical studies. In our multiple animal experiments to mimic the scenario of post-exposure infection, animals were first injected with a lethal dose of rabies virus, and then rescued by vaccination using either our PIKA rabies vaccine or the commercially existing vaccines. Only 20% of animals survived after being treated with the commercially existing vaccines, however 80% of the animals survived after vaccination of our PIKA rabies vaccine,” stated by Mr Yi Zhang, the Chairman of Yisheng Biopharma and the project leader of PIKA adjuvant technology.

Mr Zhang continued: “Such encouraging data is setting up good foundation to initiate a Phase II clinical study with an expanded study population and to further demonstrate clinical efficacy and safety under the accelerated vaccine regimen. We are looking forward to updating the progress on these fronts in due course.”